Fitting for a vehicle seat

ABSTRACT

In the case of a fitting ( 5 ) for a vehicle seat, in particular a latching fitting for a motor vehicle seat, having a first fitting part ( 11 ), having a second fitting part ( 12 ) which can be rotated relative to the first fitting part ( 11 ) and can be locked, having at least one latch ( 21 ) which is arranged in a manner such that it can move in the radial direction in a guide ( 15 ) of the first fitting part ( 11 ) and, for locking purposes, interacts with the second fitting part ( 12 ), on its side placed radially outward, and having an eccentric ( 25 ) which can rotate relative to the fitting parts ( 11, 12 ) and acts on the latch ( 21 ), on its side placed radially inward, in order to move said latch radially outward, the eccentric ( 25 ) acts on the latch ( 21 ) via two spaced-apart points ( 23, 31 ).

CROSS-REFERENCE TO RELATED APPLICATION

[0001] This application is a continuation of PCT/EP01/13641, which isentirely incorporated herein by reference, was filed Nov. 23, 2001,designates the U.S., and was published in German on Aug. 1, 2002.

BACKGROUND OF THE INVENTION

[0002] The present invention relates to a fitting for a vehicle seat, inparticular a latching fitting for a motor vehicle seat.

[0003] WO 00/44582 discloses a known latch fitting. In the event of asevere load in the direction of rotation, for example in the case of acrash, in which, via the backrest, a torque acts on the fitting partconnected thereto, there is the risk, if the guide and the latches whichare present are not produced with precise tolerances, of the latchestilting in the guide and, as a consequence, of the toothed overlapbetween the latch and fitting part being reduced.

BRIEF SUMMARY OF THE INVENTION

[0004] One aspect of the present invention is the provision of animproved latch fitting that is suitable for relatively high loadrequirements and can be provided in a cost-effective manner. Inaccordance with this aspect, a fitting for a vehicle seat, in particulara latching fitting for a motor vehicle seat, has a lower fitting part,an upper fitting part which can be rotated relative to the lower fittingpart, and at least one latch and an eccentric that are cooperative forselectively restricting the rotation of the upper fitting part. Thelatch is arranged for moving radially in a guide of the lower fittingpart. The eccentric is for rotating relative to the fitting parts. Whenthe eccentric rotates, it acts on a radially inward side of the latch,so that the latch moves radially outward and a radially outward side ofthe latch interacts with the upper fitting part via a meshing of teeth.The meshing restricts the rotation of the upper fitting part. Theeccentric acts on the latch via two spaced-apart points.

[0005] By the eccentric acting on the latch via two spaced-apart points,the latch, when it receives a load which acts in the circumferentialdirection and which it experiences when the upper fitting part isloaded, can be better supported on the eccentric, i.e. a blocking forcehaving a relatively large lever arm can oppose possible tilting in theguide. This retains the toothed overlap between the latch and the upperfitting part and therefore ensures the locked state. A considerableincrease in load is therefore possible. Since toothed segments are notable to tilt as much, there is simultaneously an improved performance interms of play.

[0006] Preferably, two eccentric cams are arranged on the eccentric andtwo blocking cams are arranged on the latch, in each case the cams arespaced part by a distance approximately equal to the latch width, asmeasured transversely to the guide. Apart from the improved support,this has the advantage of reducing the actuating path, since the latchcan be activated more easily. The arrangement of the blocking cams andeccentric always ensures that an equilibrium of forces can arise, evenunder manufacturing tolerances. The bearing between the blocking camsand eccentric takes place within the self-locking range, in order toprevent a transmission of torque to the eccentric. In the case of twolatches, the load is mainly conducted diagonally through the eccentricvia respective blocking cams, with the result that despite thetheoretically four-way support the static precision is maintained.

[0007] The play, which has already been reduced by the double support,is preferably further reduced by the eccentric cams having clampingsurfaces with different average distances from the center of theeccentric. A tilting movement, which is caused thereby, of the latches,which are movable in the guides owing to tolerances, compensates for thefree play. A suitable configuration ensures that the fitting has a lowamount of play and great strength.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

[0008] The invention is explained in greater detail below with referenceto two exemplary embodiments which are illustrated in the drawings, inwhich

[0009]FIG. 1 shows a section through the first exemplary embodiment,

[0010]FIG. 2 shows a vehicle seat provided with the first exemplaryembodiment,

[0011]FIG. 3 shows a partial view of the first exemplary embodiment inthe unlocked state,

[0012]FIG. 4 shows a partial view of the first exemplary embodiment inthe locked state, and

[0013]FIG. 5 shows a section through the second exemplary embodiment.

DETAILED DESCRIPTION OF THE INVENTION

[0014] In the first exemplary embodiment, for adjusting the inclinationof its backrest 3, a vehicle seat 1 of a motor vehicle has, on both ofits sides, a respective fitting 5 which is designed as a latchingfitting. The two fittings 5 are in a geared connection to each other bymeans of a transmission rod 7. A hand lever 9, which sits in arotationally fixed manner on the transmission rod 7, is used for themanual actuation of the fittings 5. The following directional detailsrefer to the cylindrical coordinate system defined by the transmissionrod 7.

[0015] Each fitting 5 has, as first fitting part, a lower fitting part11 and, as second fitting part, a upper fitting part 12, which parts areheld together in the axial direction by retaining plates (notillustrated in detail). The lower fitting part 11, which is fixed on theseat part, is provided with four guide and bearing segments 15 which,radially outward, form a cylindrically shaped bearing surface, with fourinterruptions, for a correspondingly curved, radially inwardly pointingbearing surface of the upper fitting part 12, which is designed as ahollow wheel and is fixed on the backrest. In each case two guide andbearing segments 15 together form a guide which runs radially, for atoothed segment 21 which is arranged in a radially movable manner.

[0016] Each toothed segment 21 bears, as a latch, on a convexly curvedside placed radially further outward, a multiplicity of teeth which caninteract with corresponding teeth of the upper fitting part 12, on thebearing surface thereof, in order to lock the fitting 5. The two sides,which run parallel to the radial direction, are used for guidance by theassociated two guide and bearing segments 15. That side of the toothedsegment 21 which is predominantly concavely curved and is placedradially further inward, bears two convex blocking cams 23 which are atthe greatest possible distance from each other on this side of thetoothed segment 21, i.e. are arranged in each case at the corner of oneof the two sides running parallel to the radial direction.

[0017] In order to push the two toothed segments 21 outward, aneccentric disk 25 is provided, which disk is seated in a rotationallyfixed manner on the transmission rod 7 by means of a transmissionelement 27 in the form of a bushing and which is prestressed by twospiral springs 29. On the outer circumference of the eccentric disk 25four eccentric cams 31, which project radially outward, are providedwith a respective clamping surface 33, which is curved eccentricallywith regard to the transmission rod 7. In the circumferential directionbetween the eccentric cams 31, the eccentric disk 25 springs backradially inward to such an extent that the blocking cams 23 can find ahold. A driver disk, which for the sake of clarity is not illustratedand which also sits in a rotationally fixed manner on the transmissionrod 7 by means of the transmission element 27 and which interacts in amanner known per se with the two toothed segments 21 via slot-and-pinguides, is used for returning the toothed segments 21 inward in theradial direction, i.e. for the unlocking, which is initiated by rotationof the transmission rod 7 by means of the hand lever 9.

[0018] Starting from an unlocked state in which the two toothed segments21 are situated radially inward, the prestressing of the spiral springs29 causes the eccentric disk 25 to be rotated in such a manner that theeccentric cams 31 first of all come to bear against the blocking cams33. Owing to the radially continuously increasing distance of theclamping surfaces 33 from the center of the eccentric disk 25, i.e. fromthe transmission rod 7, on further rotation the eccentric cams 31 usethe blocking cams 23 to push the toothed segments 21 outward. As soon asthe toothed segments 21 come into engagement with the upper fitting part12, the respective fitting 5 is locked. In this case, the angle betweeneach clamping surface 31 and the associated bearing surface of theblocking cam 23 lies in the self-locking range.

[0019] If, in the locked state, the upper fitting part 12 is loaded by atorque, for example in the event of a crash, the toothed segments 21 cantilt via the intermeshing teeth owing to tolerances in their guides. Thetilting is opposed by a blocking force, on account of the blocking cams23 being supported at their edge on the eccentric disk 25, specificallywith a lever arm which is large in comparison with a central support.This severely restricts the tilting, so that in the event of a crash therisk of a reduction in the toothed overlap leading to a lowerload-bearing capacity of the fitting 5, because then only a few teethare supported, is reduced, or such a reduction of the toothed overlapoccurs only at a very much later time. Loads in and counter to thedirection of travel primarily load the blocking cams 23 on thecorresponding side and relieve the others of load. As a result, the loadis conducted diagonally through the eccentric disk 25, as a result ofwhich static precision is maintained.

[0020] The second exemplary embodiment is largely identical to the firstexemplary embodiment and so components which are identical and act in anidentical manner bear reference numbers which are increased by 100. Thefitting 105 according to the second exemplary embodiment likewisecomprises a lower fitting part 111 having four guide and bearingsegments 115 on which a upper fitting part 112 is mounted rotatably andwhich serve at the same time as a guide for two toothed segments 121which can move radially in opposite directions. The toothed segments 121have two blocking cams 123 on their side pointing radially inward.

[0021] A centrally arranged eccentric 125, which is spring-loaded as inthe first exemplary embodiment, uses a respective first eccentric cam131, which trails in the loading direction, and a respective secondeccentric cam 132, which is ahead in the loading direction, to push thetwo toothed segments 121 radially outward where the toothed segments 121interact with a toothed rim (internal toothing) of the upper fittingpart 112, in order to lock the fitting 105. The eccentric cams 131 and132, which are four in total, are not precisely curved in the shape of acircular arc around the rotational axis of the eccentric 125, but havein each case a first clamping surface 133 or second clamping surface 134having an increasing radius, i.e. having an eccentric curvature. Withregard to the center of the eccentric 125, i.e. the central axis of thetransmission rod (not illustrated), each first clamping surface 133 ofthe first eccentric cam 131 is at a larger average distance (largeraverage radius) than each second clamping surface 134 of the secondeccentric cam 132. A driver disk 135, which is only illustrated in thebackground in the drawing and which is connected in a rotationally fixedmanner to the eccentric 125, is used, as in the first exemplaryembodiment, to return the toothed segments 121 in a manner known per seby means of a slot-and-pin guide.

[0022] Because of tolerances, there is play between the guide andbearing segments 115 and the toothed segments 121 in the hundredths of amillimeter range, which play would lead to a “free play” at the upperedge of the backrest. The difference, which lies approximately in thetenths of a millimeter range, between the average radii of the eccentriccams 131 and 132 ensures that the toothed segments 121 are forced into atilted position by the eccentric 125 and are kept there. The tiltedposition is illustrated in the drawing, not to scale. The tiltingmovement of the toothed segments 121 takes place until they bear on bothsides against the guide and bearing segments 115. This compensates forthe “free play” which has already been reduced by the double support.The toothed engagement between the toothed segments 121 and the toothedrim of the upper fitting part 112 is not impaired.

[0023] Owing to tolerances, this happens in most cases already at oneend of the tilting movement before the two blocking cams 123 bearagainst the two eccentric cams 131 and 132. The distance of theeccentric 125 from the toothed segment 121 is so small that very highstrengths can also be obtained on account of the high static strength ofthe double support.

[0024] For the static precision of the system, it is advantageous if thetwo supporting points between the eccentric 125 and toothed segment 121are used only at high loads, and otherwise there is only one supportingpoint in each case.

That which is claimed:
 1. A fitting for a vehicle seat, the fittingcomprising: a first fitting part including a guide; a second fittingpart mounted for rotating about an axis relative to the first fittingpart; at least one latch which is arranged in the guide of the firstfitting part for moving radially inward and outward relative to theaxis, with the latch including inner and outer sides, the inner sidebeing located radially inward of the outer side, and the outer sidebeing located radially outward of the inner side; and an eccentricmounted for rotating relative to the fitting parts so that the eccentricacts on the inner side of the latch and thereby moves the latch radiallyoutward so that the outer side of the latch interacts with the secondfitting part to restrict rotation of the second fitting part, whereinthe eccentric acts on the latch via two spaced-apart points.
 2. Afitting according to claim 1, wherein the eccentric has at least twoeccentric cams which are at a distance from each other that isapproximately equal to a width of the latch, with the width of the latchbeing measured in a direction transverse to the guide, a first of thetwo eccentric cams at least partially providing a first of the twospaced-apart points, and a second of the two eccentric cams at leastpartially providing a second of the two spaced-apart points.
 3. Afitting according to claim 2, wherein for each of the eccentric cams ofthe eccentric, the eccentric cam has an eccentrically curved clampingsurface with which the eccentric cam acts on the latch to provide therespective one of the spaced-apart points.
 4. A fitting according toclaim 2, wherein: for each of the eccentric cams of the eccentric, theeccentric cam has a clamping surface with which the eccentric cam actson the latch to provide the respective one of the spaced-apart points,and the clamping surface of one of the eccentric cams of the eccentricis at a greater average distance from the center of the eccentric thanthe clamping surface of the other eccentric cams of the eccentric.
 5. Afitting according to claim 2, wherein: the latch includes a plurality ofblocking cams for being acted on by the eccentric and for beingsupported by the eccentric, the inner side of the latch includesopposite edges, a blocking cam of the plurality of blocking cams isproximate one of the opposite edges of the inner side of the latch andat least partially provides the first of the two spaced-apart points,and another blocking cam of the plurality of blocking cams is proximatethe other of the opposite edges of the inner side of the latch and atleast partially provides the second of the two spaced-apart points.
 6. Afitting according to claim 5, wherein when the eccentric camsrespectively bear against the blocking cams, angles respectively definedbetween adjacent surfaces of the eccentric cams and the blocking camsprovide a self-locking affect.
 7. A fitting according to claim 5,wherein when the second fitting part is exposed to a load, which seeksto cause the rotation of the second fitting part, while the latch is inthe outward position: the second fitting part exerts a load on thelatch, with the load on the latch having at least a component thatextends in a loading direction which is tangential to the rotation ofthe second fitting part, a first of the blocking cams of the latch isahead of another of the blocking cams of the latch in the loadingdirection, and the latch is supported on the eccentric predominantly viathe first blocking cam.
 8. A fitting according to claim 7, wherein: thelatch is a first latch; the fitting further comprises a second latcharranged for moving radially outward and interacting with the secondfitting part to restrict the rotation of the second fitting part, inresponse to the rotating of the eccentric; the eccentric is positionedbetween the first and second latches; and when the second fitting partis exposed to the load, which seeks to cause the rotation of the secondfitting part, while the first and second latches are restricting therotation of the second fitting part: the first and second latchesreceive loads, and the first and second latches respectively conduct theloads diagonally through the eccentric.
 9. A fitting according to claim1, wherein the fitting is in combination with the vehicle seat foradjusting an inclination of a backrest of the vehicle seat.
 10. Afitting according to claim 1, wherein: the latch includes a plurality ofblocking cams for being acted on by the eccentric and for beingsupported by the eccentric, the inner side of the latch includesopposite edges, a blocking cam of the plurality of blocking cams isproximate one of the opposite edges of the inner side of the latch andat least partially provides a first of the two spaced-apart points, andanother blocking cam of the plurality of blocking cams is proximate theother of the opposite edges of the inner side of the latch and at leastpartially provides a second of the two spaced-apart points.
 11. Afitting according to claim 10, wherein when the second fitting part isexposed to a load, which seeks to cause the rotation of the secondfitting part, while the latch is in the outward position: the secondfitting part exerts a load on the latch, with the load on the latchhaving at least a component that extends in a loading direction which istangential to the rotation of the second fitting part, a first of theblocking cams of the latch is ahead of another of the blocking cams ofthe latch in the loading direction, and the latch is supported on theeccentric predominantly via the first blocking cam.
 12. A fittingaccording to claim 11, wherein: the latch is a first latch; the fittingfurther comprises a second latch arranged for moving radially outwardand interacting with the second fitting part to restrict the rotation ofthe second fitting part, in response to the rotating of the eccentric;the eccentric is positioned between the first and second latches; andwhen the second fitting part is exposed to the load, which seeks tocause the rotation of the second fitting part, while the first andsecond latches are restricting the rotation of the second fitting part:the first and second latches receive loads, and the first and secondlatches respectively conduct the loads diagonally through the eccentric.13. A fitting according to claim 12, wherein the fitting is incombination with the vehicle seat for adjusting an inclination of abackrest of the vehicle seat.
 14. A fitting according to claim 3,wherein: the latch includes a plurality of blocking cams for being actedon by the eccentric and for being supported by the eccentric, the innerside of the latch includes opposite edges, a blocking cam of theplurality of blocking cams is proximate one of the opposite edges of theinner side of the latch and at least partially provides the first of thetwo spaced-apart points, and another blocking cam of the plurality ofblocking cams is proximate the other of the opposite edges of the innerside of the latch and at least partially provides the second of the twospaced-apart points.
 15. A fitting according to claim 14, wherein whenthe eccentric cams respectively bear against the blocking cams, anglesrespectively defined between adjacent surfaces of the eccentric cams andthe blocking cams provide a self-locking affect.
 16. A fitting accordingto claim 15, wherein when the second fitting part is exposed to a load,which seeks to cause the rotation of the second fitting part, while thelatch is in the outward position: the second fitting part exerts a loadon the latch, with the load on the latch having at least a componentthat extends in a loading direction which is tangential to the rotationof the second fitting part, a first of the blocking cams of the latch isahead of another of the blocking cams of the latch in the loadingdirection, and the latch is supported on the eccentric predominantly viathe first blocking cam.
 17. A fitting according to claim 16, wherein:the latch is a first latch; the fitting further comprises a second latcharranged for moving radially outward and interacting with the secondfitting part to restrict the rotation of the second fitting part, inresponse to the rotating of the eccentric; the eccentric is positionedbetween the first and second latches; and when the second fitting partis exposed to the load, which seeks to cause the rotation of the secondfitting part, while the first and second latches are restricting therotation of the second fitting part: the first and second latchesreceive loads, and the first and second latches respectively conduct theloads diagonally through the eccentric.
 18. A fitting according to claim4, wherein: the latch includes a plurality of blocking cams for beingacted on by the eccentric and for being supported by the eccentric, theinner side of the latch includes opposite edges, a blocking cam of theplurality of blocking cams is proximate one of the opposite edges of theinner side of the latch and at least partially provides the first of thetwo spaced-apart points, and another blocking cam of the plurality ofblocking cams is proximate the other of the opposite edges of the innerside of the latch and at least partially provides the second of the twospaced-apart points.
 19. A fitting according to claim 18, wherein whenthe second fitting part is exposed to a load, which seeks to cause therotation of the second fitting part, while the latch is in the outwardposition: the second fitting part exerts a load on the latch, with theload on the latch having at least a component that extends in a loadingdirection which is tangential to the rotation of the second fittingpart, a first of the blocking cams of the latch is ahead of another ofthe blocking cams of the latch in the loading direction, and the latchis supported on the eccentric predominantly via the first blocking cam.20. A fitting according to claim 19, wherein: the latch is a firstlatch; the fitting further comprises a second latch arranged for movingradially outward and interacting with the second fitting part torestrict the rotation of the second fitting part, in response to therotating of the eccentric; the eccentric is positioned between the firstand second latches; and when the second fitting part is exposed to theload, which seeks to cause the rotation of the second fitting part,while the first and second latches are restricting the rotation of thesecond fitting part: the first and second latches receive loads, and thefirst and second latches respectively conduct the loads diagonallythrough the eccentric.